Wrapper for smoking article, smoking article, and method of making same

ABSTRACT

A wrapper for a smoking article which, when wrapped about a tobacco column, provides improved sidestream smoke reduction, improved ash formation, and improved mainstream smoke taste and sidestream smoke odor subjectives. These objectives are attained by forming a single cellulosic sheet containing a filler combination of magnesium hydroxide activated carbon, and calcium carbonate. In addition, the sheet may be treated with a burning chemical such as potassium citrate, an organic acid such as citric acid, and a sugar such as sucrose. Considerable latitude exists in regard to sheet basis weight, filler levels, sheet porosity, burn rate and size press solution treatment in order to optimize product requirements.

SUMMARY OF THE INVENTION

This invention relates to a smoking article wrapper which, when providedwith a suitable tobacco column, produces less particulate sidestreamsmoke than do cigarettes fabricated with conventional cigarette paperwrappers, produces a well formed ash which clings tightly withoutpremature flaking and burns at an acceptable rate, and to methods ofproducing same.

BACKGROUND OF THE INVENTION

The reduced sidestream smoke cigarette paper patents which describemagnesium oxide/hydroxide as paper fillers, which are assigned to OlinCorporation, Ecusta Corporation or P. H. Glatfelter Company, and whichdisclose burning chemical types and levels are U.S. Pat. Nos. 4,231,377;4,450,847; 4,881,557; and 4,915,118. These patents claim alkali metalacetates, citrates, nitrates, carbonates and tartrates as burningchemical types at levels in the sheet ranging from 0.5% to 8.0%.

The Kimberly-Clark Corporation and Cookson Group, plc patents dealingwith reduced sidestream smoke cigarette paper are U.S. Pat. Nos.4,461,311 and 4,804,644. These patents disclose the use of sodium andpotassium salts of carbonic, formic, acetic, propionic, malic, lactic,glycolic, citric, tartaric, fumaric, oxalic, malonic, nitric, andphosphoric acids at levels in the sheet up to 16% by weight (levels upto 25% are also disclosed) and high superficial surface area, thermallystable fillers.

U.S. Pat. No. 3,744,496, assigned to Olin Corporation, discloses acarbon-filled paper to wrap cigarettes and/or cigars, preferably used asan inner liner, with regular cigarette paper or cigar wrapper as anouter wrap.

OBJECTS OF THE INVENTION

The purpose of this invention is to provide a cigarette paper or cigarwrapper which, when fabricated into a cigarette or cigar with a suitabletobacco column, statically burns at an acceptable rate, produces alight-colored, well formed ash which clings tightly without prematureflaking, delivers both mainstream and sidestream smoke with asubjectively pleasant taste and aroma, and has significantly reducedsidestream smoke. More specifically, these desirable properties areachieved by a mixture of magnesium hydroxide, activated carbon andcalcium carbonate to produce a base cigarette paper or cigar wrapper,and this paper is subjected to treatments as described in U.S. patentapplication Ser. No. 514,333, filed Apr. 26, 1990, (acid treatment) andSer. No. 514,885, filed Apr. 26, 1990, (sugar addition). Furthersidestream aroma and mainstream taste improvements may be effected byabsorption onto all or part of the activated carbon such flavorants asmenthol, vanillin, ethyl vanillin, propenyl guaethol, and glycyrrhizawhich are released by the heat of the burning zone to enter thesidestream and mainstream smoke.

DETAILED DESCRIPTION OF THE INVENTION

It has been found that by putting activated carbon in the furnish of thepaper, along with magnesium hydroxide and calcium carbonate, andincorporating the teachings of U.S. patent applications Ser. No. 514,533(acid treatment) and Ser. No. 514,885 (sugar addition), an enhancementin sidestream smoke reduction is obtained over magnesiumhydroxide/calcium carbonate only, while obtaining a significantimprovement in ash properties and mainstream taste subjectives. Theresulting cigarette is distinctly light to dark gray in color, dependingon the particle size and level of carbon in the paper. The truly novelfindings in this work are the improvements in sidestream smokereduction, ash, and subjective taste properties of cigarettes wrapped inpapers containing a mixture of magnesium hydroxide, activated carbon andcalcium carbonate over the same papers with only magnesium hydroxide andcalcium carbonate or activated carbon and calcium carbonate fillers.

    ______________________________________                                        PARAMETERS OF THE INVENTION                                                   ______________________________________                                        Carbon content:   2.0 to 40%                                                  Preferred         5.0 to 25%                                                  Magnesium Hydroxide content:                                                                    2.0% to 35%                                                 Preferred         5.0% to 20%                                                 Calcium Carbonate content:                                                                      5.0% to 40%                                                 Preferred         10% to 30%                                                  Basis Weight:     25 gm/m.sup.2 to 100 gm/m.sup.2                             Preferred         35 gm/m.sup.2 to 65 gm/m.sup.2                              Porosity:         1 to 25 Coresta                                             Preferred         5 to 12 Coresta                                             Burning Chemical: Alkali metal salts of                                                         organic or inorganic acids                                                    selected from the group                                                       consisting of citric, malic,                                                  lactic, glycolic, tartaric,                                                   fumaric, maleic, malonic,                                                     glutaric, adipic, acetic,                                                     succinic, hydrochloric and                                                    phosphoric.                                                 Burning Chemical Addition Rate:                                                                 0.5% to 6.0%                                                Acid Addition Rate:                                                                             1.0% to 10% acid compatible                                                   with the alkali metal salt                                                    burning chemical.                                           Sugar Addition Rate:                                                                            1.0% to 10% mono-, di-, tri-                                                  or poly-saccharides.                                        Flavorant:        Adsorbed onto the carbon.                                   Smoking Articles: Cigarettes, cigars, and the                                                   like.                                                       ______________________________________                                    

The size of the particles of the incorporated activated carbon issignificant in that the smaller the particles, the darker the finishedpaper sheet, and if the particles are too large, they cause "sparking"which would not be tolerable in a commercial smoking article.

The preferred particle size (by ASTM method E-11) measured on an air-jetsieve would be 98+% through 325 mesh. Questionable particle size wouldbe larger than 8.4% on 200 mesh, 25.6% on 325 mesh, and 65.1% through325 mesh.

                  TABLE I                                                         ______________________________________                                        TASTE SUBJECTIVES                                                             ______________________________________                                        Cigarette Base Paper                                                                       10% Magnesium Hydroxide                                                       10% Activated Carbon (North American                                          Carbon Co.) (98.6%, 325 mesh)                                                 GX248                                                                         20% Calcium Carbonate                                                         Porosity = 9 Coresta                                                          Basis Weight = 45 gm/m.sup.2                                     Test Cigarettes - Commercial 100 mm "Lights" brand with                       standard paper removed and replaced with the experimental                     reduced-sidestream-smoke cigarette papers.                                    ______________________________________                                                                       Subjective                                     Additive/Burning Chemical                                                                      Odor/Taste Results                                                                          Preference                                     ______________________________________                                        1)   5.6% Potassium Citrate                                                                        Cigar type aroma                                                                            5                                                               Harsh         (worst)                                                         After Taste                                              2)   5.6% Potassium Citrate                                                                        Normal Aroma  3                                                  +            Less Harsh                                                    2.3% Citric Acid                                                                              Less After Taste                                         3)   5.6% Potassium Citrate                                                                        Cigar Aroma   4                                                  +            Less Harsh                                                    6.0% Sucrose    Less After Taste                                         4)   5.6% Potassium Citrate                                                                        Normal Aroma  l                                                  +            Smooth        (best)                                          2.3% Citric Acid                                                                              No After Taste                                                   +                                                                          4.5% Sucrose                                                             5)   5.6% Potassium Citrate                                                                        Normal Aroma  2                                                  +            Peppery                                                       2.3% Citric Acid                                                                              No After Taste                                                    +                                                                         6.0 Sucrose                                                              ______________________________________                                    

It is observed from the above study that the addition of both citricacid and sucrose to the base paper containing magnesium hydroxide,activated carbon, and calcium carbonate gives improvements in sidestreamaroma and mainstream taste, and when the two are combined, the bestproducts are produced in terms of subjective taste and aroma properties.

                                      TABLE II                                    __________________________________________________________________________    SIDESTREAM REDUCTION                                                          Test Cigarettes - Commercial 100 mm "Lights" brand with standard paper        removed and replaced with the                                                 experimental reduced-sidestream-smoke cigarette papers.                                      Basis weight                                                                         %   %    %   Coresta                                    Cigarette Paper                                                                              gm/m.sup.2                                                                           CaCO.sub.3                                                                        Mg(OH).sub.2                                                                       Carbon                                                                            Porosity                                                                           SBR.sup.1                                                                         SSGR.sup.2                                                                        TSS.sup.3                     __________________________________________________________________________    Control - Ecusta 12556                                                                       25     30   0    0  25   56.7                                                                              2.13                                                                              28.3                          Heavyweight + 1% K.sub.3 Citrate                                                             45     20   0    0  9    50.7                                                                              1.46                                                                              20.2                          LSS - Mg(OH).sub.2.sup.4                                                                     45     30  10    0  9    56.7                                                                              0.99                                                                              13.2                          LSS - Mg(OH).sub.2 /Carbon.sup.4                                                             45     25  10    5  9    55.8                                                                              0.91                                                                              13.0                          LSS - Mg(OH).sub.2 /Carbon.sup.4                                                             45     20  10   10  9    50.9                                                                              0.79                                                                              12.1                          LSS - Mg(OH).sub.2 /Carbon.sup.4                                                             45     15  10   15  9    45.6                                                                              0.71                                                                              11.2                          LSS - Mg(OH).sub.2 /Carbon.sup.4                                                             45     10  10   20  9    41.4                                                                              0.62                                                                              11.6                          LSS - Mg(OH).sub.2 /Carbon.sup.4                                                             45     20  10   10  18   61.7                                                                              0.99                                                                              12.4                          LSS - Mg(OH).sub.2 /Carbon.sup.4                                                             45     15  10   15  13   59.3                                                                              0.80                                                                              10.4                          LSS - Mg(OH).sub.2 /Carbon.sup.4                                                             35     20  10   10  9    43.3                                                                              0.78                                                                              14.1                          LSS - Mg(OH).sub.2 /Carbon.sup.4                                                             55     20  10   10  9    53.7                                                                              0.74                                                                              11.2                          LSS - Carbon.sup.4                                                                           45     30   0   10  18   65.2                                                                              1.03                                                                              12.6                          __________________________________________________________________________     .sup.1 SBR = Static Burn Rate  mg/min                                         .sup.2 SSGR = Sidestream Generation Rate  mg/min                              .sup.3 TSS = Total Sidestream  mg/cigarette                                   .sup.4 Burning Chemical Content = 5.6% potassium citrate, 2.3% citric         acid, 6% sucrose                                                         

COMMENTS - TABLE II

In reviewing Table II results, it will be observed that the combinationof magnesium hydroxide/carbon/calcium carbonate-filled papers are givingthe greatest sidestream smoke reductions, as judged by the sidestreamsmoke generation rate (SSGR)--being greater as the level of carbon inthe paper is increased. Previous studies have shown the sidestreamreduction also increases with the increase in the level of magnesiumhydroxide, but the overall subjective ash properties decline withincreases in the magnesium hydroxide level. The total sidestream tar(TSS) is greatly influenced by the burn rate of the cigarette and ishigher the slower the static burn rate. Burn rate control can beeffected by burning chemical type and level, basis weight, sheetporosity, filler type and level, and the type and level of magnesiumhydroxide in the paper.

                  TABLE III                                                       ______________________________________                                        ASH PROPERTIES                                                                Test Cigarettes - Commercial 100 mm "Lights" brand with                       standard paper removed and replaced with the experimental                     reduced-sidestream-smoke cigarette papers.                                    Cigarette Paper                                                                          Static Ash     Puffed Ash                                          ______________________________________                                        Control.sup.1                                                                            Tight shrinkage                                                                              Tight shrinkage                                                Light gray     Light gray                                                     No flake fall-off                                                                            No flake fall-off                                              Solid sheath   Small adhering flakes                               Mg(OH).sub.2 - 35%.sup.2                                                                 Outward flare  No shrinkage                                                   Light gray     Light gray                                                     Total ash fall-off                                                                           Moderate flake fall-off                                        Cracked sheath Cracked sheath                                      Mg(OH).sub.2 - 10%.sup.3                                                                 No shrinkage   Tight shrinkage                                                Light gray     Light gray                                                     Minimal flake fall-off                                                                       No flake fall-off                                              Cracked sheath Cracked sheath                                      Mg(OH).sub.2 - 10%.sup.4                                                                 Tight shrinkage                                                                              Tight shrinkage                                     Carbon - 10%                                                                             Light gray     Light gray                                                     No flake fall-off                                                                            No flake fall-off                                              Solid sheath   Small adhering flakes                               ______________________________________                                         .sup.1 Ecusta 12556 Cigarette Paper: 30% Calcium Carbonate, 25 Coresta        Porosity, 25 gm/m.sup.2, 0.55% Citrate burning chemicals.                     .sup.2 35% Magnesium hydroxide, 5% Calcium Carbonatefilled 45 gm/m.sup.2      paper treated to contain 5.6% potassium citrate, 2.3% citric acid, and        6.0% sucrose, 10 Coresta porosity.                                            .sup.3 10% magnesium hydroxide, 30% calcium carbonatefilled 45 gm/m.sup.2     paper treated to contain 5.6% potassium citrate, 2.3% citric acid, and        6.0% sucrose, 9 Coresta porosity.                                             .sup.4 10% magnesium hydroxide, 10% activated carbon, 20% calcium             carbonatefilled 45 gm/m.sup.2 paper treated to contain 5.6% potassium         citrate, 2.3% citric acid, and 6.0% sucrose, 9 Coresta porosity.         

COMMENTS - TABLE III

It will be observed in reviewing Table III results, the combination ofmagnesium hydroxide/carbon/calcium carbonate-filled paper is giving ashproperties very similar to that obtained with regular (control)cigarette paper with no significant differences being observed betweenthese two papers.

                                      TABLE IV                                    __________________________________________________________________________    ADSORBED FLAVORANT                                                            Test Cigarettes - Commercial 100 mm "Lights" brand with standard paper        removed and replaced with the experimental reduced-sidestream-smoke           cigarette papers.                                                                       Sidestream Reduction                                                                          Taste/Aroma                                         Cigarette Paper                                                                         Porosity                                                                           SBR.sup.1                                                                         SSGR.sup.2                                                                        TSS.sup.3                                                                        Taste    Aroma                                      __________________________________________________________________________    Vanillin.sup.4                                                                          9    48.2                                                                              0.78                                                                              12.2                                                                             Very low vanillin                                                                      Mild vanillin                              Ethyl Vanillin 10%.sup.5                                                                9    47.4                                                                              0.77                                                                              12.3                                                                             Low vanillin                                                                           Strong vanillin                            Propenyl Guaethol.sup.6                                                                 8    43.1                                                                              0.64                                                                              11.5                                                                             Low sweet                                                                              Sweet                                      Ethyl Vanillin 5%.sup.7                                                                 9    46.9                                                                              0.74                                                                              12.3                                                                             Very low vanillin                                                                      Mild Vanillin                              __________________________________________________________________________     .sup.1 Static Burn rate  mg/min.                                              .sup.2 SBR = Sidestream Generation Rate  mg/min.                              .sup.3 TSS = Total Sidestream Tar  mg/cigarette                               .sup.4 Activated Carbon/Vanillin Preparation - Dissolve 1.0 gm. Vanillin      in 2.0 gm. 95% Ethyl Alcohol solution and add with constant stirring to       10.0 gms. of GX203 Activated Carbon from North American Carbon, Inc.. Let     stand in closed container overnight before using to prepare handsheets.       .sup.5 Activated Carbon/Ethyl Vanillin  10% Preparation. Same as footnote     4, except Ethyl Vanillin is used in place of Vanillin.                        .sup.6 Activated Carbon/Propenyl Guaethol Preparation. Same as footnote 4     except Propenyl Guaethol is used in place of Vanillin.                        .sup.7 Activated Carbon/Ethyl Vanillin  5% Preparation. Same as footnote      4, except only 0.5 gms. of Ethyl Vanillin is used in place of the             Vanillin.                                                                

I claim:
 1. A wrapper for smoking articles such as cigarettes, cigars,and the like, comprising a cellulosic fiber sheet containing magnesiumhydroxide, calcium carbonate and activated carbon; wherein the contentof magnesium hydroxide is from 5.0% to 20%; the content of the calciumcarbonate is from 10% to 30%; and the content of the activated carbon isfrom 5% to 25%; further including 1.0% to 10% of an appropriatelycompatible acid; and 1.0% to 10% mono-, di-, tri-, or poly-saccarides.2. The wrapper, as defined in claim 1, further including 0.5% to 6.0%alkali metal salts of organic and inorganic acids selected from thegroup consisting of citric, malic, lactic, glycolic, tartaric, fumaric,maleic, malonic, glutaric, adipic, acetic, succinic, hydrochloric, andphosphoric.
 3. A smoking article comprising a tobacco charge and awrapper comprising a cellulosic fiber sheet containing magnesiumhydroxide, calcium carbonate and activated carbon; wherein the contentof magnesium hydroxide is from 5.0% to 20%; the content of the calciumcarbonate is from 10% to 30% and the content of the activated carbon isfrom 5% to 25%; and further including 1.0% to 10% of an appropriatelycompatible acid, and 1.0 to 10% mono-, di-, tri-, or poly-saccarides. 4.The smoking article, as defined in claim 3, further including 0.5% to6.0% alkali metal salts of organic or inorganic acids selected from thegroup consisting of citric, malic, lactic, glycolic, tartaric, fumaric,maleic, malonic, glutaric, adipic, acetic, succinic, hydrochloric andphosphoric.
 5. A method for reducing the visible sidestream smokeemanating from a smoking article, improving the ash properties andimproving the mainstream taste subjectives comprising wrapping thetobacco charge in a combustible cellulosic sheet containing magnesiumhydroxide, calcium carbonate and activated carbon; wherein the contentof magnesium hydroxide is from 5.0% to 20%; the content of the calciumcarbonate is from 10% to 30% and the content of the activated carbon isfrom 5% to 25%; and further including 1.0% to 10% of an appropriatelycompatible acid; and 1.0% to 10% mono-, di-, tri-, or poly-saccharides.6. The wrapper, as defined in claim 5, further including 0.5% to 6.0%alkali metal salts of organic or inorganic acids selected from the groupconsisting of citric, malic, lactic, glycolic, tartaric, fumaric,maleic, malonic, glutaric adipic, acetic, succinic, hydrochloric andphosphoric.
 7. A wrapper for smoking articles such as cigarettes,cigars, and the like, comprising a cellulosic fiber sheet containingmagnesium hydroxide, calcium carbonate and activated carbon; wherein thecontent of the magnesium hydroxide is from 2.0% to 40%; the content ofthe calcium carbonate is from 5.0% to 40%, and the content of theactivated carbon is from 2.0% to 40%; and further including a flavorantadsorbed on the activated carbon, said flavorant selected from the groupconsisting of menthol, vanillin, ethyl vanillin, propenyl guaethol, andglycyrrhiza which is released by the heat of the burning zone to enterthe sidestream and mainstream smoke.
 8. A smoking article comprising atobacco charge and a wrapper comprising a cellulosic fiber sheetcontaining magnesium hydroxide, calcium carbonate and activated carbon;wherein the content of magnesium hydroxide is from 2.0% to 40%; thecontent of the calcium carbonate is from 5.0% to 40%, and the content ofthe activated carbon is from 2.0% to 40%; and further including aflavorant adsorbed on the activated carbon, said flavorant selected fromthe group consisting of menthol, vanillin, ethyl vanillin, propenylguaethol, and glycyrrhiza which is released by the heat of the burningzone to enter the sidestream and mainstream smoke.
 9. A method forreducing the visible sidestream smoke emanating from a smoking article,improving the ash properties and improving the mainstream tastesubjectives comprising wrapping the tobacco charge in a combustiblecellulosic sheet containing magnesium hydroxide, calcium carbonate andactivated carbon; wherein the content of magnesium hydroxide is from2.0% to 40%; the content of the calcium carbonate is from 5.0% to 40%and the content of the activated carbon is from 2.0% to 40%; and furtherincluding absorbing a flavorant on the activated carbon, said flavorantselected from the group consisting of ethyl vanillin, propenyl guaethol,and glycyrrhiza which is released by the heat of the burning zone enterthe sidestream and mainstream smoke.